Flexible diaphragm pump



March 27, 1951 GEHRES ET AL 2,546,302

FLEXIBLE DIAPHRAGM PUMP Filed June 4, 1946 INVENTORL HEW|TTA.G EH RES.

EY CHARLES M Bov RD.

ATTO R N EYS Patented Mar. 27, 1951 FLEXIBLE DIAPHRAGM PUMP Hewitt A. Gehres and Charles M. Bovard, Mount Vernon, Ohio, assignors to Cooper-Bessemer Corporation, Mount Vernon,

tion of Ohio Ohio, at corpora- Application June 4, 1946, Serial No. 674,273

6 Claims.

The invention relates to heavy duty pumps such as are used for circulating drilling mud or other abrasive carrying liquids, and wherein the liquids or sludge being pumped are kept out of contact with the pump plungers by interposed flexible diaphragms which are exposed on one side to the pumping chamber and on the other side to the chamber in which the pump plunger works, the latter chamber containing a clean and lubricating liquid which transmits the pressure from the pump plunger to the diaphragm. In pumps of the above type as heretofore constructed, there has been a tendency of the fluid on one side of the diaphragm to gain progressively as compared to the amount of fluid on the other side thereof, thus eventually distorting the flexible diaphragm to its breaking point; usually the build up of fluid has occurred on the plunger side of the diaphragm, causing the flexible medium to blow out into the side of the chamber which contains the fluid to be pumped.

The present invention aims primarily to provide a pump of the above character which is constructed to avoid the above objections. Another object of the invention is to provide a pump construction of the above type wherein a plurality of diaphragms of the character above referred to,

may be served by one pump plunger. Further objects and advantages of the invention however will be in part obvious and in part specifically referred to in the description hereinafter contained which, taken in conjunction with the accompanying drawings, discloses a preferred form of pump construction to operate in accordance with the invention; the disclosure however should .be considered as merely illustrative of the principles of the invention in its broader aspects. In the drawings, the single figure is a vertical sectional view taken through a pumping unit which is constructed to operate in accordance with the invention.

The invention is disclosed as applied to a pump having a working liquid containing chamber or cylinder I which should be understood as filled with lubricating oil or similar non-injurious fluid. Within the chamber I reciprocates a plunger 2 which is shown as mounted in one end wall of chamber l by means of a gland 3 and packing 4. The plunger 2 is shown as fixed to a slidable cross head 5 which should be understood as reciprocated in appropriate manner not necessary to be :shown or described in detail since appropriate driving mechanisms are known in the art.

;1 A flexible diaphragm 6 of rubber-like material is subjected to the liquid pressure, pulsations in chamber i which are produced by reciprocation of plunger 2. In the illustrated embodiment of the invention this diaphragm .6 is in the form of a disk having its peripheral edge fixedly held in position against the adjacent wall 7 of the main frame of the pump, by means of a ring 8 and cer tain other parts as hereinafter referred to. Thus the diaphragm 6 may flex back and forth in response to liquid pressure variations in the chamher I, and the movable portion of the diaphragm is provided with a relatively rigid backing, which in the illustrated form comprises a circular plate on one side of diaphragm 6, and a shell member it the base or end wall II of which is clamped by bolts 12 to hold the central active portion of diaphragm 6 securely between the members 9 and l I. While we prefer to construct the diaphragm '6 of flexible material as above described, the invention in its broader aspects is applicable in general to pumping members interposed between the chamber I and the hereinafter mentioned pumping chamber l3, and which are mounted to move back and forth between the chambers in response to pressure fluctuations in chamber 1, so as to afford pumping action.

On the left hand side of diaphragm 6, as the parts appear in the drawings, is located a pumping chamber through which flows the liquid or slurry to be pumped, this chamber having appropriate intake and delivery valves communicating therewith. In the form shown, the incoming fluid to be pumped passes into chamber [3 through a passageway l4 beneath the chamber. A valve seat member [5 constitutes one wall of chamber I3, the member I5 being held in position as shown by a spacer member It which is secured thereto by a central bolt H, the member It being in turn held in position by a cap I 8 clamped in place by bolts I9.

An annular delivery passageway 29 leads from the pumping chamber l3 to an appropriate offtake conduit 2!, and a ring type delivery valve 22 is shown as seating upon rings 23 of rubber-like elastic material, which are carried by the valve seat member [5 and which serve to form a hydraulic seal for the passageway 29, during the suction movement of diaphragm t. The valve 22 is yieldingly urged toward seating position by an appropriate number of springs 2d. Assuming that an appropriate intake valve is provided for chamber l3 (for example as hereinafter described), the fluid to be pumped will be drawn into pumping chamber l3 as the diaphragm 6 moves from the left into the position shown in vthe drawings, and as the plunger 2 advances into 3 chamber 1, diaphragm 6 will move to the left from the position shown in the drawings and thereby cause liquid previously drawn into chamber 13 as above described, to be discharged past valve 28 into the delivery conduit 2 l.

The diaphragm 6 is of much larger diameter than plunger 2 and accordingly the stroke of the diaphragm will be much reduced as compared to that of the plunger; for example, in the form shown in the drawings, a plunger having a four inch stroke will produce a travel of the diaphragm amounting only to about inch. Accordingly the distortion of the diaphragm under normal operating conditions is very slight, and since the pressures on the opposite sides of the diaphragm are approximately equal there is no undue tendency of the diaphragm to distort or break.

In accordance with the present invention, we employ in connection with the above described diaphragm, a stop mechanism which limits the travel of the diaphragm at the suction end of its stroke, the diaphragm being preferably springpressed to cause it to assume the same Zero position at the end of each suction stroke. In the particular form of the invention which is illustrated, the shell it is provided with an annular flange 25 which abuts the end wall 28 of chamber 1 under the above conditions, the end wall 26 thus serving as a stop preventing further travel of the diaphragm 6 toward the right as the parts appear in the drawings. In the form shown the shell 50 loosely surrounds the plunger 2, and a compression spring 2'5 encloses the shell id, the spring employed being strong enough to overcome the fluid pressure existing in chamber l at the end of the suction stroke, which pressure is normally somewhat greater than atmospheric. Accordingly at the end of the suction stroke of the plunger, the diaphragm 6 and shell is will always return to the position shown in the drawings.

A working liquid reservoir 28 is connected to the chamber 1 through a conduit 28, and under normal operating conditions insures a constant supply of working liquid to chamber i. In the form shown, any working liquid which leaks past the packing 4 is collected in a sump at the bottom of the pump casing, and is circulated through pipe 3!, pump 32 and pipe 33, back into reservoir 28. The liquid level in reservoir 28 is normally maintained constant by an overflow pipe 34 which leads back to sump 35. A check valve 35 in conduit 29 prevents the flow of working liquid from chamber I back into reservoir 28 during the pressure stroke of plunger 2. If during the suction stroke of plunger 2, a vacuum tends to form in chamber l due to loss of working liquid therefrom, the check valve 35 will open to make up the lost liquid within the chamber. Thus if any vacuum should be created in the apparatus, it will normally occur in the chamber l3 rather than chamber l. Conversely there is no danger of over-filling the chamber 1 with working liquid, so as to progressively build up fluid pressure therein which would overstrain and break the diaphragm B.

Preferably a safety device is employed in connection with reservoir 28 which is responsive to loss of liquid level in the reservoir such as will occur in case the diaphragm should break. If that happens there will be less resistance to pumping oil from reservoir 28 into pump chambier 13, than to drawing further liquid to be pumped into the chamber through passageway 14. Accordingly the liquid level in chamber 28 will drop rapidly in case the diaphragm breaks,

and a suitable float 35 or the like as schematically indicated in the drawings, may be provided in reservoir 23 to close an electrical circuit 31 when the liquid level in the reservoir is abnormally low and thus actuate a device 39 which either produces a signal, or as an equivalent shuts down the pump to prevent injury such as will occur if the plunger 2 is operated under conditions where a break in the diaphragm 3 permits abrasive material to enter from chamber l3 into contact with plunger 2 and the surfaces with which it engages.

The apparatus also preferably includes a stop member 40 to prevent over-travel of the diaphragm 6 at the delivery end of its stroke. In the form shown this stop as is secured by a screw All to the central portion of the valve seat member l5, and is engaged by the plate 9 which serves as one of the backing members for diaphragm 6.

In the illustrated form of the invention a ring 42 having openings 43 therethrough is interposed between the valve seat member 15 and the ring 8 which clamps the periphery of diaphragm 6 in position, a sinuous spring 44 serving to maintain a resilient pressure on ring 8, all of the above mentioned parts being ultimately held in position by the bolts 19.

The illustrated form of the invention shows a construction wherein a plurality of flexible diaphragms of the character above described maybe served by a single plunger. The disclosed apparatus includes a second chamber in which may be understood as similar to the chamber i above described, except that no plunger corresponding to plunger 2 is provided therein; the chamber HA also has associated with it a diaphragm BA. This diaphragm and immediately associated parts, may be understood as the same in construction and mode or" operation as the corresponding parts already described. The chambers i and IA are in communication through a passageway 45 and thus upon reciprocation of plunger 2, chamber IA and diaphragm 6A partake equally of the pressure fluctuations created by plunger 2, and are similarly related to the working liquid in supply reservoir 28.

The diaphragm has associated with it a pumping chamber l3A; this and immediately associated parts may be understood as similar to those associated with the pumping chamber it), except as now to be specifically mentioned. In the particular form of the invention which is illustrated, the pumping chamber i31 has associated therewith an intake valve member 22A which is yieldingly pressed by an appropriate number of springs 24A against rings 23A similar to the rings 23, and intake port 28A communicates with an intake conduit 26 for the fluid to be pumped. Thus on the suction strokes of plunger 2, the intake valve 22 lifts from oh its seat and admits the fluid to be pumped to both or the chambers i3 and HA, the delivery valve 22 being closed under these conditions; during the pressure stroke of plunger 2, intake valve 22A is held closed and delivery valve 22 is unseated to cause the liquid being pumped to discharge from both of the chambers l3 and ISA into the discharge conduit 2|.

While the invention has been disclosed as applied to a pump of the above described specific construction, it should be understood that changes may be made therein without departing from the invention in its broader aspects, within the scope of the appended claims.

We claim:

1. A pump of the character described having a working liquid containing chamber, a pumping chamber having intake and delivery valves communicating therewith, a diaphragm of flexible material interposed between said chambers, a reciprocating plunger operating in said first mentioned chamber for subjecting the working liquid to fluctuating pressure to produce suction and delivery movements of said diaphragm with respect to said pumping chamber, a relatively rigid member fixed to the movable portion of said diaphragm, and a stop member disposed peripherally outward of said plunger in said first mentioned chamber and positioned to limit the movement of said diaphragm at the suction end of its path of travel, said pump having a part movable with said diaphragm which projects longitudinally of said plunger into the space which surrounds said plunger within said first mentioned chamber and is engageable with said stop member, to limit the position of said diaphragm at the suction end of its path of travel.

2. A pump of the character described having a working liquid containing chamber, a pumping chamber having intake and delivery valves oommunicating therewith, a diaphragm of flexible material interposed between said chambers, a plunger reciprocable in said first mentioned chamber to produce suction and delivery movements of said diaphragm with respect to said pumping chamber through the medium of the working liquid, a shell member disposed within said first mentioned chamber and loosely enclosing said plunger, said shell being fixed to the movable portion of said diaphragm, and stop means engageable with said shell member to limit the position of said diaphragm at the suction end of its path of travel.

3. A pump or the character described having a working liquid containing chamber, a pumping chamber having intake and delivery valves communicating therewith, a diaphragm of flexible material interposed between said chambers, a plunger reciprocable in said first mentioned chamber to produce suction and delivery movements of said diaphragm with respect to said pumping chamber through the medium of the working liquid, a shell member disposed within said first mentioned chamber and loosely enclosing said plunger, said shell being fixed to the movable portion of said diaphragm, and stop means engageable with said shell member to limit the position of said diaphragm at the suction end of its path of travel, said pump also having a spring yieldingly urging said shell member into engagement with said stop means.

4. A pump of the character described having a working liquid containing chamber, a pumping chamber having intake and delivery valves communicating therewith, a diaphragm of flexible material interposed between said chambers, means for subjecting the working liquid to fluctuating pressure to produce suction and delivery movements of said diaphragm with respect to said pumping chamber, a relatively rigid member fixed to the movable portion of said diaphragm,

V and a stop member positioned to limit the movement of said diaphragm at the suction end of its path of travel, said pump having a part movable with said diaphragm and engageable with said stop member to limit the position of said diaphragm at the suction end of its path of travel, a working fluid supply reservoir connected to said first mentioned chamber, means operating normally to maintain a constant level of liquid within such reservoir, check valve means interposed between said reservoir and said first mentioned chamber and responsive to loss of liquid in said first mentioned chamber to admit further liquid thereto, and signal means associated with said reservoir which is responsive to loss of liquid level therein.

5. A pump of the character described having a working liquid containing cylinder, a reciprocable plunger mounted in one end wall of said cylinder, a diaphragm of flexible material mounted across the opposite end of said cylinder, a 'shell member reciprocably mounted in said chamber and having an end wall fixed to said diaphragm, a spring mounted within said cylinder concentrically with said shell member, said pump having a pumping chamber disposed on the opposite side of said diaphragm with respect to said shell, in take and delivery valves communicating with said pumping chamber, said plunger operating to produce suction and delivery movement of said diaphragm with respect to said pumping chamber, and said spring yieldingly urging said shell into engagement with stop means associated with said cylinder, to limit the position of said diaphragm at the suction end of its path of travel.

6. A pump of the character described having a working liquid containing chamber, a reciprocating plunger operating in said chamber for subjecting the working liquid in said chamber to fluctuating pressure, a plurality of diaphragms of flexible material each having one side thereof exposed to pressure fluctuations of such working liquid, as produced by said plunger, said pump having pumping chamber means exposed to the other sides of said diaphragms, said pumping chamber having an intake valve substantially alined with one of said diaphragms and a delivery valve substantially alined with another of said diaphragms.

HEWITT A. GEHRES. CHARLES M. BOVARD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 731,241 Steiner June 16, 1903 1,922,264 Shimer Aug. 15, 1933 2,183,421 Brady Dec. 12, 1939 2,303,597 Adelson Dec. 1, 1942 2,343,962 Dodson Mar. 14, 1944 FOREIGN PATENTS Number Country Date 792,627 France Jan. 7, 1936 

